We propose to study the biochemical changes occurring during neurometamorphosis with the view that these studies will aid in defining the mechanism of neural development in general. The organism to be used is the insect, Manduca sexta. We intend to study changes occurring in the whole central nervous system, brain, individual ganglia and isolated glial or neural cells from these organs. In addition, we propose to study changes occurring in synaptosomes during neurometamorphosis. The activities to be measured are enzymes associated with neurotransmitters or the cyclic nucleotide systems. The synthesis of various proteins during neural development will also be studied as will neurotransmitters.